I feel like anyone who views this, myself included, will be immediately struck by the sheer movement you've managed to create with the smoke and lava. The angle of this piece also adds to the feeling that everything is sliding.The details you've added are really extraordinary, especially those in the rocks and in the smoke. I feel like there could be a bit more color or shade variation in the lava to add to the feeling of heat, but it is nonetheless very effective as-is. As far as composition goes, I think that there could maybe be a bit more circular movement in the center to guide the eye through the piece. There is a little of this in the middle left side where the general pattern of the smoke curls up, but in the upper right-ish side the smoke and the rocks create almost a right angle, which sort of blocks the movement. If there was more of a curl there, I believe it would help prevent this pause. Also, I feel like a little more depth could be created if there were a few more tiny bits of rock peeking out of the smoke; the fact that there are large ones and then nothing at all makes it seem like the landscape has no middle ground, only high points and low points. Otherwise, I think that the composition is very well thought-out. Especially because you say that this is a WIP, this is really fantastic. You've created excellent mood with the colors, and the details really glow. Fantastic!